Abstract
Purpose :
Ocular graft versus host disease (OGvHD) is a common complication of allogeneic hematopoietic stem cell transplantation (HSCT) and frequently manifests as keratoconjunctivitis sicca (KCS). The aim of this study was to evaluate the efficacy of a single subconjunctival (SC) dose of adeno-associated virus (AAV) gene therapy encoding human leukocyte antigen G (HLA-G) to induce ocular immune tolerance and inhibit clinical signs of OGvHD.
Methods :
The major histocompatibility mismatch chronic OGvHD murine model was created, as described by Perez (2016; doi:10.1016/j.bbmt.2016.07.012). Animal use was approved by the NC State University IACUC (protocol #20-122-B). To create the murine OGvHD model, bone marrow (BM) and splenocytes were collected from male C57BL/6 (n=4) mice 6-8 weeks of age. Female BALB/c mice (n=12), aged 6-8 weeks, were administered 700cGy total body X-ray irradiation, as optimized in our preliminary studies. Two hours after irradiation, mice were injected into a lateral tail vein with 1x107 BM cells and 1x106 splenocytes. Following injection, body weights and tear production (phenol red test) were recorded, and scores (0-4) (observer blinded to treatment groups) of the eyelid margins, corneal opacity, and corneal fluorescein were collected through day 44 after HSCT. At 7 days following HSCT, mice received in both eyes either a single SC injection of AAV8-HLA-G1&5 (1x109vg/eye), no treatment (n=4), or 2μL of CsA 1% solution twice daily (n=4).
Results :
Eyelid scores of eyes dosed with AAV-HLA-G were significantly lower than untreated or CsA treated eyes from 24-44 days after HSCT (p<0.03 Wilcoxon). Cornea scores of eyes dosed with AAV-HLA-G were significantly lower than untreated or CsA treated eyes from 27-44 days after HSCT (p<0.01, Wilcoxon). Fluorescein scores of eyes dosed with AAV-HLA-G and CsA were significantly lower than untreated eyes from 30-44 days after HSCT (p<0.02, Wilcoxon). No statistically significant difference in weight or tear production was observed between any of the three treatment groups.
Conclusions :
These results further validate the function of HLA-G in the murine model, indicate that the SC therapeutic route targets relevant ocular tissues, and provides strong support that HLA-G-based gene therapy will be an effective single vector treatment for OGvHD. Further evaluation of AAV-HLA-G based therapeutics are warranted for ocular surface and intraocular immune-mediated diseases.
This is a 2021 ARVO Annual Meeting abstract.